Bar feed mechanism for lathe

ABSTRACT

A novel construction of a bar-feed mechanism for lathe such as a turret lathe is composed of a main structure of the mechanism slidable on a guide means supported by a base structure, an operational tubular member slidably and freely rotatably included in said main structure, a lever means pivotably mounted on said main structure for driving said operational tubular member longitudinally and reciprocatingly in said main structure, a seizing means which seizes and releases the bar material in cooperation with the advance and retraction of said operational tubular member, a hydraulic cylinder provided traversingly between an end of the lever means and said main structure, and another hydraulic cylinder which shifts the main structure for a predetermined distance along the guide.

inventor HirofumiTomiyama 1000 Akiwa, Ueda-shi, Japan 816,305

Apr. 15, 1969 Jan. 26, 1971 Appl. No. Filed Patented BAR FEED MECHANISM FOR LATHE 3 Claims, 13 Drawing Figs.

US. Cl

Int. Cl Field of Search References Cited UNITED STATES PATENTS 2,695,096 ,1 1/1954 Gridley .1:

3,094,042 6/1963 Diener Primary Examiner-Gerald M. Forlenza Assistant Examiner-Frank E. Werner Att0rney-Holman, Glascock, Downing and Seebold ABSTRACT: A novel construction of a bar-feed mechanism for lathe such as a turret lathe is composed of a main structure of the mechanism slidable on a guide means supported by a base structure, an operational tubular member slidably and freely rotatably included in said main structure, a lever means pivotably mounted on said main structure for driving said operational tubular member longitudinally and reciprocatingly in said main structure, a seizing means which seizes and releases the bar material in cooperation with the advance and retraction of said operational tubular member, a hydraulic cylinder provided traversingly between an end of 226/165X the lever means and said main structure, and another hydrau- 226/165X lic cylinder which shifts the main structure for a predeter- 226/165 mined distance along the guide.

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INVENTOR ATTORNEYS BAR FEED MECHANISM FOR LATHE BACKGROUND OF THE INVENTION This invention relates to hydraulically operated bar-feed mechanisms foruse, for instance, in turret lathes, and more particularly to the type thereof wherein a bar material is fed in a step-by-step manner to the lathe by means of the bar-feed mechanism which is advanced or retracted depending on whether the material bar is seized by a seizing means or released therefrom.

In this kind of mechanism, it is essential that the bar material be kept in the seized condition until the front tip of the material abuts against a stop on the lathe, and also that the bar material not be released before it is firmly caught by the chuck of the lathe. If the bar material is released before the instant as described above, the front end of the bar material may be slightly retracted from the position determined by the stop, and this could result in a deleterious inaccuracy of the product. I

However, this essential feature of the conventional material feed mechanism inevitably creates an inconvenience whereby the headstock of the lathe cannot be rotated until the material is firmly caught by the chuck of the lathe and the material in the material feed mechanism is thereby released. This inconvenience isconcomitantly accompanied by the disadvantage of the necessity of repetition of stopping and restarting of the head stock each time the machining of the product is completed.

Without requiring further elucidation, it is apparent that a machine frequently started and stopped entails a greater probability of causing wear or trouble in the operational parts of the machine than a machine continuously operated, and the operational efficiency and the power consumption in the former case are inferior.

Another type of the material feed mechanism wherein the above described shortcomings are intended to be overcome has also been proposed. In such a mechanism, a plurality of rolls are provided at the front end of the seizing means in the feeding mechanism, and the bar material is seized by these rolls so that the head stock of the lathe is thereby allowed to be rotated continuously.

However, even with such devices, if the bar material is of a square or hexagonal cross section, the desired object cannot be fully accomplished.

SUMMARY OF THE INVENTION Therefore, the primary object of this invention is to provide a novel material feeding mechanism, wherein a provision is made so that the head stock of the lathe can be operated continuously regardless of the cross-sectional configuration of the bar material.

The above described object of this invention can be accomplished by a novel construction of the material feed mechanism comprising: a main structure of the mechanism slidable on a guide means supported by a base structure, an operational tube slidably and freely rotatably included in the main structure, a lever means pivotally mounted on the main structure for driving the operational tube longitudinally in the main structure, a seizing means which seizes and releases the bar material in cooperation with the advance and retracting of the operational tube, a hydraulic cylinder provided between an end of the lever means and the main structure, and another hydraulic. cylinder which shifts the main structure for a predetermined distance along the guide.

These and other features of the invention will be better understood from the following description, of a preferred embodirnent thereof, when read in conjunction with the accompanying drawings, wherein like parts are designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a front elevation showing a material feed mechanism according to the present invention;

' to bar materials having square, hexagonal, and round cross sections, respectively;

FIG. 8 shows a bushing which is fabricated for each application to conform with the cross section of the bar material;

FIG. 9 is a perspective view showing the material feed mechanism in accordance with the present invention together with the chucking lever of the parent lathe;

FIG. 10 is a diagram showing the mechanical and electrical linkage for the operation of the material feed mechanism in connection with that of the parent lathe;

FIGS. 11 and I2 are electrical circuit diagrams for the material feed mechanism in accordance with the present invention; and

FIG. 13 is a hydraulic circuit diagram of the same mechanism.

DESCRIPTION OF THE INVENTION Referring at first to FIGS. 1 and 9, there is indicated a main structure, generally designated by 'numeral 1, of a material feed mechanism in accordance with this invention. The main structure 1 is mounted on a guiding member 3 supported on a base structure 2 in a manner such that the main structure 1 is slidable reciprocatingly on the guiding member 3. A cylindrical body 4 is supported by bearings 5 inside of the main structure I so that it is not slidable relative to the main structure 1. Inside of the cylindrical body 4, a tubular member 6 is mounted in a manner such that the member 6 is freely slidable relative to the cylindrical body 4 and is also rotatable together with the cylindrical body 4. On both ends of the tubular member 6, engaging rings 7, 8 are fixedly mounted.

Furthermore, a seizing device main body 9 is fixedly mounted on a flange portion 40 provided on the rearward end of the cylindrical body 4 by means of, for instance, bolts 10, and on the surface of the seizing device main body 9, for instance, four radially disposed channel shaped grooves 35 are cut through. A lever 11 is pivotally mounted, for instance, in each of the vertically disposed grooves 35 on the main body 9 of the seizing device, and an arm of the lever 1 l is received in the engaging ring 8, while the other arm of the lever 11 is received in a recessed portion 12a on each of jaws 12 which are freely slidably inserted, in this case, in the vertically disposed channel shaped grooves 35. A seizing member 13 is fixed on each of the jaws 12 by means of bolts 14 and nuts 15, the latter being included inside of the T-shaped groove in the jaws 12.

Supplementary seizing blocks 13a are mounted on the surface of the seizing device main body 9 in the grooves, horizontally disposed in the mechanism shown, so that the blocks 13a are fixed to the positions by means of bolts 14a and nuts 15a which are adjustably received inside of the grooves. As is apparent from FIGS. 5, 6, and 7, supplementary seizing members 13b having a seizing angle adapted to each of the different cross-sectional configuration of the bar materials 34 can be selectively mounted on the supplementary seizing blocks 13a.

A lever 16 is pivotally mounted on the main structure 1 around a lateral shaft 17, on one end of which are provided a pair of rollers rs freely rotatably to engage with the engaging ring 7, on the other end of which is pivotally mounted a piston rod 191; for a hydraulic cylinder 19, and the hydraulic cylinder 19 includes a cylinder member 19a which is pivotally mounted on the main structure 1 through a bracket 20.

Another hydraulic cylinder unit 21 includes a cylinder member 21a which is formed as an integral part of the main structure 1. The hydraulic cylinder unit 21 further includes a piston rod 21lb which extends inside of the cylinder member 21a in the forward and afterward direction, and both ends of the piston rod 21b are connected to the base structure 2.

A dog plate 24 is provided on the bracket and includes dogs 22 and 23 which cooperate with limit switches 25, 26 fixedly mounted on the base structure 2. Another dog plate 29 is attached to the lever 16 and includes dogs 27, 28 which cooperate with limit switches 30, 31 mounted at the bottom of the cylinder member 19a.

1t will be further apparent from the drawings that the base structure 2 of this material feed mechanism is rigidly connected to the rearward end of the parent lathe by means of a connecting tube 32, and that the bar material 34 is guided through a guide member 33 provided at the rear end of this material feed mechanism. Bushings 36, 360 are also provided for guiding the bar material 34 and are attached on the engag ing ring 7 and on a material supporting member 2a of the base structure 2, respectively. These bushings 36, 36a are specif cally fabricated for adaption to the cross-sectional configuration of the bar materials. A backstop 45 of well known construction is provided on the rear portion of this material feed mechanism, and this is employed when an auxiliary rod is used for feeding an already shortened bar material to the lathe. In this case it is necessary to prevent the backward shift of the auxiliary rod because the rod is not caught by the chuck of the lathe.

The operation of the material feed mechanism according to the invention will now be disclosed in detail.

When the machining on the lathe is completed for one-unit of the product, and the chuck of the continuously running lathe is released, a signal is generated to cause an application of hydraulic pressure to a space 19c of the hydraulic cylinder unit 19 shown in H0. 2. As a result, the lever 16 is swung in the clockwise direction and the tubular member 6 is thereby shifted forward through the roller 18 and the engaging ring 7. By this forward shift of the tubular members 6, the lever 11 is rotated counterclockwise, and the seizing members 13 seize the bar material 34.

Immediately before the completion of the seizure, the swinging motion of the lever 16 causes the dog 27 to abut the limit switch 30. This creates a signal which produces a hydraulic pressure in the chamber 2lcof the hydraulic cylinder unit 21, and the bar material 34 seized as described above is shifted forward together with the main structure 1 of the material feed mechanism.

In the meantime, when the dog 22 abuts the limit switch 25, the forward end of the bar material 34 at the same time abuts against the stop provided on the lathe, and the feeding motion of the feed mechanism is thereby stopped. After the stopping of the feeding motion, the seizure of the bar material by means of the seizing members 13 is continued to prevent separation of the end of the bar material from the stop. Then the chuck in the lathe seizes the bar material 34. The seizure of the chuck issues a signal, and a hydraulic pressure is applied to the chamber 19d of the hydraulic cylinder unit 19, whereby the seizure of the bar material by the seizing members 13 is released.

in the course of these operational actions, there is a period during which the bar material 34 is seized by both the seizing members 13 and the chuck. However, this does not cause any trouble because the entire seizing device, consisting of cylindrical body 4, main body 9, levers 11, engaging ring 8, jaws 12, and seizing members 13, and tubular member 6, and also engaging ring 7 are rotated in unison with the bar material 34.

Then a hydraulic pressure is applied to the chamber 21d of the hydraulic cylinder unit 21, and the entire assembly consisting of the main structure 1 and the associated portions, which are shifted forward together with the bar material, are retracted. Meanwhile, the dog 23 abuts against the limit switch 26, and the main structure 1 of the material feed mechanism is stopped at the rearmost position of the reciprocating cycle. The above described operation is repeated through several cycles until the bar material is consumed, and the rear end of the material passes through the seizing members 13, whereupon the feeding operation of this mechanism cannot be continued any more.

A new material is then furnished to the point where the forward end of the new material passes the seizing members 13 and abuts against the rearward end of the preceding material, which is thereby pushed step-by-step until it is completely machined on the lathe.

As described above, the supplementary seizing members 13b are provided in addition to the seizing member 13, and since the supplementary seizing members 13b can be selected freely for adaption to the cross-sectional configuration of the bar material, the latter of any configuration can be furnished through the material feeding mechanism without interrupting the continuous rotation of the head stock of the lathe. In this case, the supplementary seizing members 13b also serve to maintain the bar material in the position and to suppress vibration of the material which might damage the bar material.

Examples of hydraulic and electrical control of the material feed mechanism according to this invention will now be described with reference to FIGS. 10, 11, 12, and 13.

it should be noted that all of the operational signal are generated by pushbutton switches and limit switches, and also that some of the interlocking circuits of the electrical control circuit shown in FIG. 11 are omitted for clarity of illustration.

When, after energization of the electric control circuit, a pushbutton switch PB-2 is depressed, a relay CR-2 is energized and the main hydraulic pressure motor is started. It will now be assumed that an automatic operation is to'be accomplished, and a pushbutton PB-3 is depressed, whereby an automatic operation signal relay CR-3 is energized and self-supported. (When automatic operation is not being carried out, the operational members, obviously, are operated by manual control in the same order as described hereafter.)

Energization of the CR-3 relay in turn energizes a headstock starting relay CR-4, and the head-stock of the lathe is thereby started. When the machining for one unit of the product is completed, the material feed mechanism according to this invention is operated. For this purpose, a relay CR-16 is first energized by the advance of a turret-slide 37 to its forward extremity, thereby operating the limit switch LS-39. Energization of the relay CR-16 in turn energizes a relay CR- 5, and an electromagnetic valve SOL-5 is opened for releasing the chuck 40 on the'head-stock. The energization of the relay CR-S also energizes a' relay CR-9 which .in turn operates an electromagnetic valve SOL-9, and pressurized fluid is introduced into the hydraulic cylinder unit 19.

As a result, the cylinder rod 19b retracts, and the lever 16 connected with the cylinder rod 19b is swung in the clockwise direction. At the initial stage of the swinging motion of the lever 16, the bar material 34 is seized by the seizing members 13. Further swinging of the lever 16 after the seizure of the bar material causes the dog 27 to abut against the limit switch LS- 30 and a signal generated by the operation of the limit switch LS-30 activates ac ylinder advancing relay CR-l 1 after a time present in a timer TR-2, the relay CR-ll being thereafter selfheld. Activation of the CR-ll relay causes energization of an electromagnetic valve SOL-11, which in turn causes an application of the hydraulic pressure to the hydraulic cylinder unit 21, and the cylinder rod 21b is thereby advanced. The advancement of the cylinder rod 21b causes the material feed mechanism 1 to advance together with the bar material 34.

When the advancement of the material feed mechanism 1 operates a limit switch LS-25 at the forward extremity of the path by means of a dog 22, after a time preset in a timer TR-3, a relay CR-l2 is operated and self-held. The operation of the relay CR-12 immediately deenergizes the relay CR-S and the electromagnetic valve SOL-5 is closed. Feeding of the bar material is thereby stopped. The operation of the relay CR-l 2 also energizes a relay CR-8, and an electromagnetic valve SOL-8 is operated. The operation of the electromagnetic valve SOL-8 furnishes pressurized fluid to a chuck cylinder unit 41, and a chucking lever 42 is swung around to cause the chuck to close and a dog 43 to abut against a chuck-closure confirming switch LS-44. When the switch LS-44 is operated, a relay CR-l0 is energized, which in turn deenergizes the relay CR-9 arid the electromagnetic valve SOL-9 is closed. The cylinder rod 1% in the hydraulic cylinder unit 19 is thereby advanced for rotating the lever 16 in the counterclockwise direction, and the seizing members 13 are thereby caused to release the material at the early stage of the backward movement of the lever 16. When the relay CR-9 is deenergized, the relay CR-ll is released and the relay CR-13 is energized to be self-held. With the operation of the relay CR-13, an electromagnetic valve SOL-l3 is opened, and pressurized fluid is introduced into the hydraulic cylinder unit 21 causing the cylinder rod 21b to retract. When the cylinder rod 21b arrives at the rearward extremity, the dog 23 abuts against the limit switch LS'-26, whereby the relay CR-lS is energized. Energization of the relay CR-IS is turn operates the relay CR4 and the above described operation is repeated. In the circuit of FIG. 11: S S S S S S S S S 5, and S are, respectively, return pushbutton stopper-position determining contact, pushbutton for stopping the main shaft, contact for determining individual driving, stopper retracting contact, stopper position determining contact, chuck opening switch, chuck closing switch, stopper forward end contact, contact for determining individual driving, and stopper forward end contact. In the circuits of FIGS. 11 and 12, CR,, CR CR are contacts which are respectively operated by energization of the corresponding relays CR-l, CR-Z, CR-16, and rightside black spots corresponding to number 1, 2, 3 36 on the left-side correspond, respectively to the following output signals and operations In FIG. 13, PV in a compressor motor for generating pressurized hydraulic medium to be supplied to various cylinders of the apparatus of the present invention.

Although the invention has been described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that numerous changes may be made therein without departing from the true spirit of the invention as defined in the appended claims.

lclaim:

1. A bar-feed mechanism for a lathe comprising a base structure, guiding means supported on said base structure, a main structure slidably mounted relative to said guiding means for reciprocation thereon, a tubular member slidably and rotatably mounted relative to said main structure for reciprocation and rotation relative thereto, lever means having opposite end portions, pivot means pivotally mounting said lever means relative to said main structure intermediate said end portions, and engaging ring mounted on said tubular member for movement therewith, a feed seizing means including a plurality of seizing members, linkage means operatively interconnecting said seizing members with said tubular member for moving said seizing members into and out of seizing relationship with a bar material in response to reciprocating sliding movement of said tubular member relative to said main structure, a first hydraulic means operatively interposed between one of said end portions of said lever means and said main structure for pivoting said lever means about said pivot means relative to main structure, roller means carried by said other end portion of said lever means and engaged with said engaging ring for movement of said engaging ring and thereby said tubular member in response to pivotal movement of said lever means, a second hydraulic means operatively associated with saidmain structure for slidingly reciprocating said main structure relative to said guiding means, means for selectively actuating said first hydraulic means to move said seizing members into seizing relationship with a bar material, means for selectively actuating said second hydraulic means as the bar material is being seized to slidingly reciprocate said main structure relative to said guiding means in a first direction toward the lathe, means for selectively actuating said first hydraulic means to move said seizing members out of seizing relationship with the bar material after said main structure has been slidingly reciprocated relative to said building means in said first direction, and means to selectively actuate said second hydraulic means after the bar material has been released by said seizing members to slidingly reciprocate said main structure relative to said guiding means in a second direction opposite to said first direction.

2. A barfeed mechanism according to claim 1 further including stationary supplementary seizing members carried by said seizing means and functioning to assist in supporting the bar material as it is fed by said mechanism and suppressing any vibration in the bar material.

3. A bar-feed mechanism according to claim I wherein said means for selectively actuating said first hydraulic means to move said seizing member out of seizing relationship with the bar material is responsive to seizing of the bar material by a chuck in the lathe. 

1. A bar-feed mechanism for a lathe comprising a base structure, guiding means supported on said base structure, a main structure slidably mounted relative to said guiding means for reciprocation thereon, a tubular member slidably and rotatably mounted relative to said main structure for reciprocation and rotation relative thereto, lever means having opposite end portions, pivot means pivotally mounting said lever means relative to said main structure intermediate said end portions, and engaging ring mounted on said tubular member for movement therewith, a feed seizing means including a plurality of seizing members, linkage means operatively interconnecting said seizing members with said tubular member for moving said seizing members into and out of seizing relationship with a bar material in response to reciprocating sliding movement of said tubular member relative to said main structure, a first hydraulic means operatively interposed between one of said end portions of said lever means and said main structure for pivoting said lever means about said pivot means relative to main structure, roller means carried by said other end portion of said lever means and engaged with said engaging ring for movement of said engaging ring and thereby said tubular member in response to pivotal movement of said lever means, a second hydraulic means operatively associated with said main structure for slidingly reciprocating said main structure relative to said guiding means, means for selectively actuating said first hydraulic means to move said seizing members into seizing relationship with a bar material, means for selectively actuating said second hydraulic means as the bar material is being seized to slidingly reciprocate said main structure relative to said guiding means in a first direction toward the lathe, means for selectively actuating said first hydraulic means to move said seizing members out of seizing relationship with the bar material after said main structure has been slidingly reciprocated relative to said building means in said first direction, and means to selectively actuate said second hydraulic means after the bar material has been released by said seizing members to slidingly reciprocate said main structure relative to said guiding means in a second direction opposite to said first direction.
 2. A bar-feed mechanism according to claim 1 further including stationary supplementary seizing members carried by said seizing means and functioning to assist in supporting the bar material as it is fed by said mechanism and suppressing any vibration in the bar material.
 3. A bar-feed mechanism according to claim 1 wherein said means for selectively actuating said first hydraulic means to move said seizing member out of seizing relationship with the bar material is responsive to seizing of the bar material by a chuck in the lathe. 